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jeremyhyltonjeremyhylton
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rename compile.py to pycodegen.py
fix imports remove parse functions and visitor code track name change: Classdef to Class add some comments and tweak order of visitXXX methods get rid of if __name__ == "__main__ section
1 parent 8c78341 commit 7fab23e

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Lines changed: 50 additions & 352 deletions

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‎Lib/compiler/pycodegen.py‎

Lines changed: 25 additions & 176 deletions
Original file line numberDiff line numberDiff line change
@@ -5,7 +5,7 @@
55
a generic tool and CodeGenerator as a specific tool.
66
"""
77

8-
from p2c import transformer, ast
8+
from compiler import parseFile, ast, visitor, walk, parse
99
from pyassem import StackRef, PyAssembler, TupleArg
1010
import dis
1111
import misc
@@ -18,143 +18,6 @@
1818
import struct
1919
import types
2020

21-
def parse(path):
22-
f = open(path)
23-
src = f.read()
24-
f.close()
25-
t = transformer.Transformer()
26-
return t.parsesuite(src)
27-
28-
def walk(tree, visitor, verbose=None, walker=None):
29-
if walker:
30-
w = walker()
31-
else:
32-
w = ASTVisitor()
33-
if verbose is not None:
34-
w.VERBOSE = verbose
35-
w.preorder(tree, visitor)
36-
return w.visitor
37-
38-
def dumpNode(node):
39-
print node.__class__
40-
for attr in dir(node):
41-
if attr[0] != '_':
42-
print "\t", "%-10.10s" % attr, getattr(node, attr)
43-
44-
class ASTVisitor:
45-
"""Performs a depth-first walk of the AST
46-
47-
The ASTVisitor will walk the AST, performing either a preorder or
48-
postorder traversal depending on which method is called.
49-
50-
methods:
51-
preorder(tree, visitor)
52-
postorder(tree, visitor)
53-
tree: an instance of ast.Node
54-
visitor: an instance with visitXXX methods
55-
56-
The ASTVisitor is responsible for walking over the tree in the
57-
correct order. For each node, it checks the visitor argument for
58-
a method named 'visitNodeType' where NodeType is the name of the
59-
node's class, e.g. Classdef. If the method exists, it is called
60-
with the node as its sole argument.
61-
62-
The visitor method for a particular node type can control how
63-
child nodes are visited during a preorder walk. (It can't control
64-
the order during a postorder walk, because it is called _after_
65-
the walk has occurred.) The ASTVisitor modifies the visitor
66-
argument by adding a visit method to the visitor; this method can
67-
be used to visit a particular child node. If the visitor method
68-
returns a true value, the ASTVisitor will not traverse the child
69-
nodes.
70-
71-
XXX The interface for controlling the preorder walk needs to be
72-
re-considered. The current interface is convenient for visitors
73-
that mostly let the ASTVisitor do everything. For something like
74-
a code generator, where you want to walk to occur in a specific
75-
order, it's a pain to add "return 1" to the end of each method.
76-
77-
XXX Perhaps I can use a postorder walk for the code generator?
78-
"""
79-
80-
VERBOSE = 0
81-
82-
def __init__(self):
83-
self.node = None
84-
85-
def preorder(self, tree, visitor):
86-
"""Do preorder walk of tree using visitor"""
87-
self.visitor = visitor
88-
visitor.visit = self._preorder
89-
self._preorder(tree)
90-
91-
def _preorder(self, node):
92-
stop = self.dispatch(node)
93-
if stop:
94-
return
95-
for child in node.getChildren():
96-
if isinstance(child, ast.Node):
97-
self._preorder(child)
98-
99-
def postorder(self, tree, visitor):
100-
"""Do preorder walk of tree using visitor"""
101-
self.visitor = visitor
102-
visitor.visit = self._postorder
103-
self._postorder(tree)
104-
105-
def _postorder(self, tree):
106-
for child in node.getChildren():
107-
if isinstance(child, ast.Node):
108-
self._preorder(child)
109-
self.dispatch(node)
110-
111-
def dispatch(self, node):
112-
self.node = node
113-
className = node.__class__.__name__
114-
meth = getattr(self.visitor, 'visit' + className, None)
115-
if self.VERBOSE > 0:
116-
if self.VERBOSE == 1:
117-
if meth is None:
118-
print "dispatch", className
119-
else:
120-
print "dispatch", className, (meth and meth.__name__ or '')
121-
if meth:
122-
return meth(node)
123-
124-
class ExampleASTVisitor(ASTVisitor):
125-
"""Prints examples of the nodes that aren't visited
126-
127-
This visitor-driver is only useful for development, when it's
128-
helpful to develop a visitor incremently, and get feedback on what
129-
you still have to do.
130-
"""
131-
examples = {}
132-
133-
def dispatch(self, node):
134-
self.node = node
135-
className = node.__class__.__name__
136-
meth = getattr(self.visitor, 'visit' + className, None)
137-
if self.VERBOSE > 0:
138-
if self.VERBOSE == 1:
139-
if meth is None:
140-
print "dispatch", className
141-
else:
142-
print "dispatch", className, (meth and meth.__name__ or '')
143-
if meth:
144-
return meth(node)
145-
else:
146-
klass = node.__class__
147-
if self.VERBOSE < 2:
148-
if self.examples.has_key(klass):
149-
return
150-
self.examples[klass] = klass
151-
print
152-
print klass
153-
for attr in dir(node):
154-
if attr[0] != '_':
155-
print "\t", "%-12.12s" % attr, getattr(node, attr)
156-
print
157-
15821
class CodeGenerator:
15922
"""Generate bytecode for the Python VM"""
16023

@@ -311,7 +174,7 @@ def visitFrom(self, node):
311174
self.emit('IMPORT_FROM', name)
312175
self.emit('POP_TOP')
313176

314-
def visitClassdef(self, node):
177+
def visitClass(self, node):
315178
self.emit('SET_LINENO', node.lineno)
316179
self.emit('LOAD_CONST', node.name)
317180
for base in node.bases:
@@ -660,17 +523,14 @@ def visitAssTuple(self, node):
660523

661524
visitAssList = visitAssTuple
662525

526+
# binary ops
527+
663528
def binaryOp(self, node, op):
664529
self.visit(node.left)
665530
self.visit(node.right)
666531
self.emit(op)
667532
return 1
668533

669-
def unaryOp(self, node, op):
670-
self.visit(node.expr)
671-
self.emit(op)
672-
return 1
673-
674534
def visitAdd(self, node):
675535
return self.binaryOp(node, 'BINARY_ADD')
676536

@@ -695,6 +555,13 @@ def visitLeftShift(self, node):
695555
def visitRightShift(self, node):
696556
return self.binaryOp(node, 'BINARY_RSHIFT')
697557

558+
# unary ops
559+
560+
def unaryOp(self, node, op):
561+
self.visit(node.expr)
562+
self.emit(op)
563+
return 1
564+
698565
def visitInvert(self, node):
699566
return self.unaryOp(node, 'UNARY_INVERT')
700567

@@ -713,6 +580,8 @@ def visitNot(self, node):
713580
def visitBackquote(self, node):
714581
return self.unaryOp(node, 'UNARY_CONVERT')
715582

583+
# bit ops
584+
716585
def bitOp(self, nodes, op):
717586
self.visit(nodes[0])
718587
for node in nodes[1:]:
@@ -729,16 +598,6 @@ def visitBitor(self, node):
729598
def visitBitxor(self, node):
730599
return self.bitOp(node.nodes, 'BINARY_XOR')
731600

732-
def visitTest(self, node, jump):
733-
end = StackRef()
734-
for child in node.nodes[:-1]:
735-
self.visit(child)
736-
self.emit(jump, end)
737-
self.emit('POP_TOP')
738-
self.visit(node.nodes[-1])
739-
end.bind(self.code.getCurInst())
740-
return 1
741-
742601
def visitAssert(self, node):
743602
# XXX __debug__ and AssertionError appear to be special cases
744603
# -- they are always loaded as globals even if there are local
@@ -757,6 +616,16 @@ def visitAssert(self, node):
757616
self.emit('POP_TOP')
758617
return 1
759618

619+
def visitTest(self, node, jump):
620+
end = StackRef()
621+
for child in node.nodes[:-1]:
622+
self.visit(child)
623+
self.emit(jump, end)
624+
self.emit('POP_TOP')
625+
self.visit(node.nodes[-1])
626+
end.bind(self.code.getCurInst())
627+
return 1
628+
760629
def visitAnd(self, node):
761630
return self.visitTest(node, 'JUMP_IF_FALSE')
762631

@@ -879,7 +748,7 @@ def visitFrom(self, node):
879748
for name in node.names:
880749
self.names.add(name)
881750

882-
def visitClassdef(self, node):
751+
def visitClass(self, node):
883752
self.names.add(node.name)
884753
return 1
885754

@@ -921,8 +790,7 @@ def __init__(self, source, filename):
921790
self.filename = filename
922791

923792
def compile(self):
924-
t = transformer.Transformer()
925-
self.ast = t.parsesuite(self.source)
793+
self.ast = parse(self.source)
926794
cg = CodeGenerator(self.filename)
927795
walk(self.ast, cg)
928796
self.code = cg.asConst()
@@ -950,22 +818,3 @@ def compile(filename):
950818
mod.compile()
951819
mod.dump(filename + 'c')
952820

953-
if __name__ == "__main__":
954-
import getopt
955-
956-
VERBOSE = 0
957-
opts, args = getopt.getopt(sys.argv[1:], 'vq')
958-
for k, v in opts:
959-
if k == '-v':
960-
VERBOSE = 1
961-
ASTVisitor.VERBOSE = ASTVisitor.VERBOSE + 1
962-
if k == '-q':
963-
f = open('/dev/null', 'wb')
964-
sys.stdout = f
965-
if not args:
966-
print "no files to compile"
967-
else:
968-
for filename in args:
969-
if VERBOSE:
970-
print filename
971-
compile(filename)

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